Graphic: how Ebola cases have grown since March

The number of infections in western Africa's Ebola outbreak has reached almost
6,000, making it by far the worst in the history of the disease. Now experts
estimate infections could quadruple to 21,000 by the end of October and
reach a staggering 1.4m by January

Scientists predicted in a WHO study this week that more than 20,000 people will be infected with Ebola by early November.

The WHO study echoed a “worst-case scenario” report from the US Centres for Disease Control and Prevention. It estimated that cases in Liberia and Sierra Leone could rocket to 1.4 million by January - in a worst-case scenario based on data obtained before the world ramped up its response.

World leaders were due to attend a meeting in New York on Ebola convened by UN Secretary-General Ban Ki-moon on Thursday.

The meeting - part of the United Nations General Assembly - will hear from US President Barack Obama and world leaders are expected to pledge help for efforts to try to contain the spread of the virus.

Mr Obama, who is sending 3,000 troops to west Africa to help health workers battle the contagion, urged other countries on Wednesday to get behind a broader international effort.

"As we speak, America is deploying our doctors and scientists - supported by our military - to help contain the outbreak of Ebola and pursue new treatments," Mr Obama told the 193-member assembly.

"But we need a broader effort to stop a disease that could kill hundreds of thousands, inflict horrific suffering, destabilise economies and move rapidly across borders."